Underfloor heating support
Here you’ll find a set of FAQs to help you diagnose and fix any underfloor heating problems.
You can also view diagrams of your UFH manifold in order to select the relevant spare parts, most of which can be bought from the Nu-Heat webstore.
If you’re still experiencing issues with a Nu-Heat underfloor heating system, please contact our Technical Support Team via techsupport@nu-heat.co.uk or call 01404 540745 between 8am and 5pm, Monday to Friday.
Underfloor Heating FAQs
Problem: Single zone not heating up
- Sticky pin valve actuator
Spray with silicon and gently ease the pin up and down until free. Do not use WD40. - Actuator failed
Check that the actuator head is proud after 3 minutes of calling for heat – if not, replace it. Alternatively, it may not be the actuator – it could be a wiring board or thermostat issue. - Faulty thermostat
Call an electrician – check for live and switched live return. - Air in loop
Download our plumbing manual and follow the procedure for filling and flushing. - Wiring issue faulty connection – dry joint
Call an electrician – check for continuity and loose connections. - Thermostat not set up correctly – E1/E2 errors
neoStat – if you are using a neoStat please view page 9 of the User Guide which explains this error code.
neoAir – if you are using a neoAir please view page 10 of the User Guide which explains this error code. - Flow gauges not been opened correctly on E-manifolds
a) Lift the white collar – do not remove completely
b) Turn the white collar anti-clockwise to unscrew the isolation valve. Three turns will fully open the valve – do not exceed this. The isolation valve must be fully open before flow rate adjustment is possible
c) Push the white collar back down to lock the isolation valve
d) Circuit flow rate can be adjusted by twisting the top of the gauge by hand to the desired setting between 0 and 4. Lift the white collar to lock the flow meter setting.
Problem: Multiple zones not working
- Circulation pump failure
Check for air in the pump – check that the pump is receiving a live signal from the Nu-Heat wiring board. - Pump relay on wiring boards
When a call for heat is present check that the relay makes a clicking sound and it switches. - Isolation valves closed on manifold
The isolation valve is open when it’s in-line with the pipework. If it’s at 90° angle to the pipe it is closed. - Blending valve pin valve stuck
Use silicon spray (not WD40) and gently ease the pin up and down until it is free. - Air ingress
Download our plumbing manual and follow the procedure for filling and flushing. - Boiler not firing (no signal)
Check that the boiler is powered up and that the wiring board is receiving a live signal on (in) and sending this signal back on (out). - No power to wiring boards
Check 5 amp fuse on power.
Problem: Heating zone permanently on
- Faulty actuator (has it been energised/de-energised prior to fitting)
The pin valve may be stuck in the up position – use silicon spray and gently ease the pin valve up and down. - Faulty thermostat
Does the thermostat have a live supply and a switched live return when it is turned up?
Problem: UFH pump running all the time
- Pump relay stuck on the wiring board
Replace the wiring board having checked the thermostat. - Faulty thermostat
Does the thermostat have a live supply and a switched live return when it is turned up? - Faulty actuator
There are no serviceable parts – replace the actuator.
Identifying your manifold for parts
Choose your manifold from the list below to help select spare parts.
Oct 1999 – Apr 2007 – Brass manifolds (OMDxx-C)
| No. | Code | Description | Buy online |
| 1 | OMD1E-C | Port extension kit | N/A |
| 2 | OMFG-C | Flow gauges | Buy Online |
| 3 | G1560-C | Pump | N/A |
| 4 | TGD-C | Temperature gauge | Buy Online |
| 5 | MPP1-A | Complete pump module | N/A |
| 6 | MPPK1-C | Pump module assembly | N/A |
| 7 | OMBV-C | Valve set | N/A |
| 8 | MPBV075-C | Blending valve | Buy Online |
| 9 | DZSW24-C | Blending valve insert | Buy Online |
| 10 | MPPT-C | Blending valve head | Buy Online |
| 11 | OMFV-C | Pin section | Buy Online |
| 12 | ALE075/14-C | Nut/olive | Buy Online |
| 13 | WPEX/xx-C | Tube | N/A |
| 14 | OMDA-C | Actuator | Buy Online |
| 15 | OMDAC-C | Actuator collar | N/A |
| 16 | GC14-C | Guide curves | Buy Online |
| 17 | OMPG-C | Pressure gauge | N/A |
| 18 | OMDS-C | Filing/flushing | N/A |
Apr 2007 – Aug 2009 – Stainless steel manifolds (OMSxx-C)
| No. | Code | Description | Buy online |
| 1 | PM1-A | Complete pump module | N/A |
| 2 | BVM1/F1(R)-C | Valve (blue) | N/A |
| 3 | OMSFG-C | Flow gauges | Buy Online |
| 4 | OMSTG-C | Temperature gauge | N/A |
| 5 | OMSVV-C | Air vent | N/A |
| 6 | OMSPV-C | Filing/flushing | N/A |
| 7 | OMSPG-C | Pressure gauge | Buy Online |
| 8 | OMSB-C | Brackets | N/A |
| 9 | ALE075/14-C | Nut/olive | Buy Online |
| 10 | Pin section | N/A | |
| 11 | UJ14-A | PEX couplers | Buy Online |
| 12 | OMDA-C | Actuator | Buy Online |
| 13 | OMDAC-C | Actuator collar | N/A |
| 14 | BVM1/F1(B)-C | Valve (blue) | N/A |
| 15 | M1/28-C | 1″ – 28mm compression | N/A |
| 16 | BC-C | Blanking cap (for ports) | Buy Online |
| 17 | BV3/4B-C | Valve (blue) | N/A |
| 17a | BV3/4R-C | Valve (red) | N/A |
| 18 | GC14-C | Guide curves | Buy Online |
| 19 | 3/4MI22-C | 3/4″ – 22mm compression | N/A |
| 20 | G1560-C | Pump | N/A |
| 21 | PM-C | Pump module/blending valve | N/A |
Aug 2009 – Oct 2010 – Brass plated manifolds (OMExx-C)
| OME Manifold | |||
| No. | Code | Description | Buy online |
| 1 | PM1-A | Complete pump module | N/A |
| 2 | OMEFM-C | Flow gauges | Buy Online |
| 3 | OMETG-C | Temperature | N/A |
| 4 | OMSVV-C | Air vent | N/A |
| 5 | OMEAV-C | Air vent | N/A |
| 6 | OMSPG-C | Pressure gauge | Buy Online |
| 7 | OMEDV-C | Filing or flushing | N/A |
| 8 | ALE075/14-C | Nut/olive | Buy Online |
| 9 | OMEPV-C | Pin section | N/A |
| 10 | OMDA-C | Actuator | Buy Online |
| 11 | OMDAC-C | Actuator collar | N/A |
| 12a | BVM1/F1(B)-C | Valve (blue) | N/A |
| 12b | BVM1/F1(R)-C | Valve (red) | N/A |
| 13 | M1/28-C | 1″ – 28mm compression | N/A |
| 14a | BV3/4B-C | Valve (blue) | N/A |
| 14b | BV3/4R-C | Valve (red) | N/A |
| 15 | UJ14-C | Joiner | N/A |
| 16 | GC14-C | Guide curves | Buy Online |
| 17 | 3/4MI22-C | 3/4″ – 22mm compression | N/A |
| 18 | G1560-C | Pump | N/A |
| 19 | PM-C | Pump module/blending valve | N/A |
Oct 2010 – Present – Stainless steel manifolds (OMSxx-C)
| No. | Code | Description | Buy online |
| 1 | PM1-A | Complete pump module | N/A |
| 2 | BVM1/F1(R)-C | Valve (blue) | N/A |
| 3 | OMSFG-C | Flow gauges | Buy Online |
| 4 | OMSTG-C | Temperature gauge | N/A |
| 5 | OMSVV-C | Air vent | N/A |
| 6 | OMSPV-C | Filing/flushing | N/A |
| 7 | OMSPG-C | Pressure gauge | Buy Online |
| 8 | OMSB-C | Brackets | N/A |
| 9 | ALE075/14-C | Nut/olive | Buy Online |
| 10 | Pin section | N/A | |
| 11 | UJ14-A | PEX couplers | Buy Online |
| 12 | OMDA-C | Actuator | Buy Online |
| 13 | OMDAC-C | Actuator collar | N/A |
| 14 | BVM1/F1(B)-C | Valve (blue) | N/A |
| 15 | M1/28-C | 1″ – 28mm compression | N/A |
| 16 | BC-C | Blanking cap (for ports) | Buy Online |
| 17 | BV3/4B-C | Valve (blue) | N/A |
| 17a | BV3/4R-C | Valve (red) | N/A |
| 18 | GC14-C | Guide curves | Buy Online |
| 19 | 3/4MI22-C | 3/4″ – 22mm compression | N/A |
| 20 | G1560-C | Pump | N/A |
| 21 | PM-C | Pump module/blending valve | N/A |
If you need any further support, you can contact our Technical Support Team via techsupport@nu-heat.co.uk or 01404 540745 between 8am and 5pm, Monday to Friday.